A continuous chemical deposition reactor may be a stand-alone process system with a continuous semiconductor wafer flow. Basic subsystems in such a system may include a wafer handling, a reaction chamber, a gas flow system, a cooling system, and an electrical system.
The wafer handling system may include wafer loaders and unloaders, wafer carriers, and a track for moving a wafer through the reactor chambers.
The reactor chamber subsystem is the site for processing the semiconductor wafer. Each chamber may include a gas supply inlet, a chamber housing, heat lamps and exhaust.
The gas flow subsystem supplies the reactant gases to each chamber, and may include valves, flow controllers and an exhaust system.
The cooling subsystem assists in maintaining the process temperature and reduces the heat radiation to the surrounding components. Both air flow and water flow may be used in the cooling subsystem.
The electrical subsystem provides subsystem control and powers the reactor, and may include power supplies, motors, sensors, valves, and one or more computer/controller.
A basic reactor and process may be as follows. A semiconductor wafer is loaded onto a carrier which enters one end of the reactor through a port and is moved successively through the various chambers and out the other end of the reactor through another port. The reactor may not be physically closed but has gas seals at each end and in between each chamber of the reactor. As an example, a reactor may include eight chambers in which the first chamber consists of a nitrogen seal, the second chamber is a preheat chamber, the next four chambers may be deposition chambers, then a cool-down chamber and the last chamber is a nitrogen seal. A typical gas supply system may supply gases for two different deposition processes which may be directed into any of the deposition chambers. Each chamber is effectively divided into two portions, a top portion and a bottom portion by the wafer carrier. The junctions between the chambers effectively isolate one chamber from the other by the flow of gases or the exhaust gases from the chambers, and gas flow or seals are used to prevent gases from escaping from the reactor chamber/junction interface.
An example of a prior art continuous chemical vapor deposition reactor may be found in U.S. Pat. No. 4,048,955.